Medical fluid containers frequently include an injection site to enable the addition of a medicament to the medical fluid. In order to maintain the sterility of the fluid which may be, for example, a dextrose solution or saline solution, the injection site should be self-sealing so that after the injection site is pierced by a needle and the needle withdrawn, container-external contaminants cannot enter the container through the injection site.
It is known to provide an injection site which includes a thin plastic membrane above which is mounted a rubber-like piece. A needle may pierce the rubber-like piece and membrane in one motion. After the needle is withdrawn, the rubber-like piece self-seals, i.e., it closes over the opening made by the needle. The rubber-like piece prevents any liquid in the container from exiting through the hole in the membrane and prevents contaminants from entering the container through the membrane.
Frequently, the rubber-like portion is frictionally mounted in and about a cylindrical tube. It has been found that the rubber-like portion is subject to accidental removal, especially after repeated injections by a needle. Accidental removal of the rubber-like portion increases the chances of contamination of the parenteral fluid. To lessen the chance of accidental removal a heat shrink band is commonly placed about the portion of the rubber-like piece that surrounds the exterior of the cylinder. Such injection sites are relatively expensive to manufacture, sometimes requiring manual assembly. Such construction also makes necessary the careful positioning of an injecting needle because part of the rubber-like portion is directly above or outside of the cylindrical tube. Medical personnel must ensure that the needle pierces the rubber-like portion in the center portion within the tube.
The present invention virtually eliminates the chance of inadvertent removal of the rubber-like portion of the injection site, enhances the self-sealing characteristics of the injection site, presents an easy target for injection and is capable of automated assembly.